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Biomedical subjects

R Lefebvre

Publications and source records attributed to R Lefebvre.

At least 55 records · Page 3Linked to original sources
PubMed1983

Improvement of cadaveric renal allograft survival by thoracic duct drainage: relation with T-lymphocyte subset modifications assessed by flow-cytometry.

Thoracic duct drainage (TDD) with reinfusion of cell-free lymph was performed in 118 prospective recipients within four months before transplantation. TDD was unsuccessful in 27 patients (A); it yielded 1-19 X 10(9) lymphocytes in 25 cases (B) and 20-185 X -10(9) in 66 cases (C). The incidence of acute rejection episodes and the requirement for early post-transplant dialysis were lower in C than in A. Six patients were studied for T-lymphocyte subsets, using monoclonal antibodies from OKT series and a monomorphic and HLA-DR (BL2) raised in our laboratory. During TDD peripheral blood lymphocyte (PBL) counts decreased and the percentage of BL2 cells increased. Simultaneously, typical small PBL were replaced by large less differentiated cells slightly labelled by OKT3, some of them bearing both OKT4 and OKT8 markers. The larger the depletion, the earlier the emergence of immature T-cells. In lymph fluid, lymphocyte counts decreased later than in blood, the proportion of T8+ cells lacking Fc receptors increased with time. Changes in B patients were less than in C. These results support the hypothesis that T-cell subset modifications represent the main immunological change accounting for better allograft prognosis.

Antibodies, Monoclonal↗
PubMed1982

[Pleural mesothelioma: 3 developmental forms].

In the medical literature, there have been fewer reports on benign pleural mesotheliomas than on their malignant counterparts. We have reviewed the clinical, radiological and pathological features of mesotheliomas seen at the Hôtel-Dieu in Montreal over the past ten years. This experience leads us to postulate that there are three types of mesothelioma. The malignant form is often typical. Pedunculated lesions most often prove to be asymptomatic and benign. However, we have identified an intermediate category where the definitive nature of the mesothelioma could only be established after long term follow-up of the biological behaviour of the tumor.

Adult↗
PubMed1982

Primary hyperaldosteronism: a pituitary--adrenal dysfunction related to a new pituitary glycopeptide?

A novel glycopeptide has been isolated from human and porcine pituitary glands. This substance is the amino-terminal fragment of pro-opiomelanocortin (POMC). The complete amino acid sequence has been determined. When tested for its steroid stimulating activity on an aldosterone secreting human adrenocortical adenoma, it was found to be more potent than angiotensin and ACTH. These results raise the interesting possibility that primary hyperaldosteronism could be related to a pituitary adrenal dysfunction.

Adenoma↗
PubMed1980

Solitary breast metastasis: first manifestation of an occult carcinoid of the ileum.

A metastasis to the breast was the first manifestation of a clinically occult ileal carcinoid in a 53 year old woman. Modified radical mastectomy was perfomed after the breast neoplasm had been interpreted clinically and pathologically as a primary carcinoma. Permanent sections demonstrated the tumor to be composed of sheets of small uniform cells subdivided into lobules by delicate vascular septa. Silver impregnation revealed the presence of argentaffin cytoplasmic granules. This feature, with the added ultrastructural findings which showed pleomorphic neurosecretory-type granules within the cytoplasm of the tumor cells strongly suggested a metastasis to the breast from a midgut carcinoid. The subsequently performed barium study of the small bowel showed an infiltrating neoplastic lesion in the terminal ileum, which after surgical excision and histologic examination proved to be two typical argentaffin carcinoids with pleomorphic cytoplasmic granules. This report thus clearly demonstrates the importance of a combined light microscopic, histochemical and ultrastructural analysis of this breast neoplasm in order to establish its metastatic origin and to separate it from a primary carcinoma or a primary carcinoid of the breast.

Breast Neoplasms↗
PubMed1975

Arterial hypertension and neurofibromatosis: renal artery stenosis and coarctation of abdominal aorta.

A 10-year-old girl had arterial hypertension, generalized neurofibromatosis, coarctation of the abdominal aorta and multiple stenoses at the origin of each renal artery. After resection of the stenotic areas and reimplantation of the renal arteries in the aorta, her arterial pressure decreased substantially. However, hypertension recurred and radiologic follow-up 4 1/2 years later showed distinct progression of the coarctation and renewed stenosis of all renal arteries at their origin. The stenotic areas showed eccentric intimal proliferation, frequently bulging into the lumen, with small nodular aggregates of smooth muscle cells and proliferation of fibrous tissue containing spindle-shaped nuclei in a palisading pattern. Hypertension associated with neurofibromatotic vascular disease has been described in 47 other patients in the literature. These patients have been young (mean age, 14 years) and predominantly male. In contrast to fibromuscular dysplasia, in which 95% of all stenoses are found in the distal two thirds of the renal arteries, in vascular neurofibromatosis more than 50% of the stenoses are found at the origin.

Adolescent↗